The Ladd Observatory is an astronomical observatory of Brown University in Providence, Rhode Island, USA. The observatory was dedicated in 1891 and is named for benefactor Herbert W. Ladd who funded the construction.
Ladd Observatory was designed by the Providence-based firm of Stone, Carpenter & Willson. The building was added to the National Register of Historic Places in 2000.
The main telescope is a 12-inch (30 cm) refractor with a lens made by John Brashear following the design of Charles S. Hastings. The equatorial mount and mechanical clock drive were made by George N. Saegmuller.
Besides astronomical research, Ladd sent out a time signal for decades. When they decided to stop the service in the 1970s, they discovered that nobody was actually receiving it.
Astronomers associated with Ladd include Winslow Upton. Frank W. Very, Frederick Slocum and Charles H. Smiley.
H. P. Lovecraft had free access to the observatory for several years and wrote astronomy articles for Providence newspapers based upon his study there between 1906 and 1918.